GATE - The JSDF and Vanadis
by Domain627
Summary: When a mysterious gateway appeared within the Ginza District, the JSDF was deployed to investigate the world that laid beyond it. There, they found themselves dealing with rivaling kingdoms, strange mysteries and medieval traditions. Will these radically different worlds be able to co-exist with one another or will there be bloodshed in the end? GATE/Vanadis Crossover.


Disclaimer: Except for original ideas, everything else belongs to their original owners.

* * *

 **GATE: The JSDF and Vanadis**

* * *

The year is 2018 and the Earth continue to remain in a state of relative stability despite the ongoing conflicts and crises. However, it was shattered when an archway of ancient architecture appeared without warning within the Ginza District.

Upon hearing the news, the Japanese Self-Defense Force was quickly deployed to the district to set up a defensive perimeter as a precaution if anything hostile appear from the so-called Gate.

Even though a week passed and nothing came through the Gate, the JSDF remained vigilant as researchers sent out several UGV drones to safely investigate what laid beyond it.

At first, they were shocked to see through the drones' cameras that it was virtually pitch black instead. Nevertheless, the drones continue to move forward until a bright light appeared at the end of the otherwise endless tunnel.

When the drones finally made it through, the researchers were shocked beyond their wildest dreams that though the Gate was another world. After scanning the surroundings, the other side of the Gate was found to be positioned in the middle of a vast plain.

Since the appearance of the Gate, specialized drones were soon deployed to analysis the composition of the air on the other side while collecting plant samples. Upon closer inspection, the researchers learned that the other world was virtually identical in not only appearance, but also habitability.

As expected, the news spread across the globe about another Earth on the other side of the Gate was staggering. Untouched by pollution and industry, this new world was no doubt rich in both land and resources.

It was no surprise that the Japanese government soon authorized the deployment of expeditionary force through the Gate, consisting of several companies of the JSDF.

However, Japan soon found itself in the middle of a political firestorm. As the only one with access to this new world and its resources, they ended up receiving more attention than they could ever dream of from virtually every country across the globe.

Among the countries showed the most interest in the Gate and the opportunities beyond were the United States, Russia and China.

The United States promises to support Japan's expeditions to the new world and also defend the country from any rogue nation that could attempt to seize the Gate by force.

Russia and China in the other hand insisted that the Gate be placed under international supervision and would no doubt petition the idea to the United Nations.

Despite all the politics, Japan still retains its monopoly of the Gate and the world beyond it as of today.

Two weeks after the appearance of the Gate however, Japan and the rest of the world learned that the new world has its dangers as well. During a routine scan for any signs of life, one of the AGV drones caught sight of a creature that was a few kilometers away from the other side of the Gate.

To their shock and awe, the researchers saw it was a real-life dragon; its scales were blue and it was estimated to be twenty-five to thirty feet tall.

While it was a scientific opportunity like no other to observe a creature that was supposed to be a myth and fantasy, they were horrified to see that the dragon was approaching the plains were the Gate resides.

After they alerted the Japanese government and JSDF about the dragon, no time was wasted as the JSDF dispatch all available air assets from nearby bases to reinforce their side of the Gate.

As the soldiers already stationed at the Gate took up defensive positions, the police were doing what they can in evacuating as many citizens from Ginza to safety.

For the researchers, they bravely stayed at their post so they could observe the dragon's movements through the drones' cameras.

While it was hoped that the dragon would ignore the Gate, the Japanese have nevertheless prepared themselves for the worst-case scenario.

Unfortunately, it was indeed the case for when the dragon arrived onto the plains, it saw the Gate and it apparently peaked its interest. The drones continue to observe the creature as it begun to slowly approached the Gate and entered the darkness within.

It been almost twenty minutes since the alert was issued and everyone quickly learned that dragons are no longer neither myth or fiction. All across the Ginza District, a ferocious roar echoed through the streets as the creature has finally reached the other side of the Gate although its body is only halfway through the structure.

Civilians who have yet to evacuate were horrified upon seeing the gigantic creature and fled in terror while the police tried to keep them calm while getting them to safety. As for the JSDF soldiers, they were bewildered at first, but they quickly recovered and begun to fired at the dragon.

However, their rifles and machines guns have barely any effect as their rounds merely bounce off its scales. Seeing that the dragon was as tough as a tank, they could only hope to keep the creature distracted and keep it from taking another step out the Gate until reinforcements arrive.

With the dragon though, it appeared to be bewildered from the mass volley of bullets. Like any other creature though, it doesn't like getting attacked and in a state of frenzy, begun to frail its claws wildly upon the structures around the Gate.

The soldiers did what they could to evade the falling debris and glass, but some were not as fortunate. Either injured or knocked out, they were unable to get away when the dragon raised its right claw above them and would have met a grisly end if not for the bravery of two soldiers.

Positioned on the top level of one of the buildings overlooking the Gate, the first one fired several shots straight into the dragon's right eye. Recoiling in pain, it instead slammed its claw onto an empty spot in the street and not onto the injured soldiers.

Upon noticing the dragon's now-blinded right eye, the other soldier then called out to the rest of the garrison to focus their fire at the creature's eyes. Forced to close its remaining eye, the dragon was distracted enough for him and several others to drag the wounded to safety.

It wasn't long however for the creature to finally decide it had enough and immediately stomped out of the Gate to wreak havoc on the Japanese.

The soldiers were worried what was going to happen next for the dragon was preparing to take to the air with its large leathery wings. However, their previous efforts brought them enough time for a squadron of Ah-1S Cobra gunships to arrive at the scene.

Their 20mm M197s were quite effective in tearing the dragon's wings to shreds; preventing it from taking flight ever again. The final blow then came from their TOW missiles, which was able penetrated its scales and pulverized its organs.

The dragon roared in agony from the barrage of these missiles and was finally finished off when one of TOWs struck its head; collapsing onto the street dead.

While several buildings were significantly damaged and dozens of JSDF soldiers were injured in the line of duty, no lives were lost during the fighting; a miraculous outcome.

After cheering for their victory, the JSDF soon once more secure the perimeter while a group of CH-47JAs arrived to transfer the remains of the dragon to a secured location for safekeeping and analysis.

Two more months have passed since then as the Gate in Japan was now encased in a protective dome with a reinforced gate. No one is sure if it could actually withstand the might of a dragon, but it would at least give the JSDF precious time in preparing their defenses.

Not only that, the expeditionary force was now properly allocated the manpower and equipment necessary to begin their exploration of the world beyond the Gate.

Today, the JSDF is about to make history as they become the first humans on Earth to venture to a brand new world...

* * *

 **Special Region – Unknown Location**

"Ah... So, this is the Special Region."

Lieutenant General Kōichirō Hazama looked out the window of his LAV and saw it was late in the night within the other world, which was dubbed the Special Region. When the Special Task Force first went through the Gate, it was early in the afternoon in Japan.

Regardless, he and his men would do what they do best and adapt to their new surroundings.

As the commanding officer of the entire operation, it was his duty to not only ensure the safety of his men, but also be the first line of defense against any hostiles that could use the Gate here to invade Japan.

With him was 1st Lieutenant Akira Yanagida, who was currently monitoring the statuses of all the units in the Special Task Force.

"All units are accounted for." He told Hazama.

"Good. All units, spread out and secure the Gate!"

Upon hearing the order, all vehicles and tanks quickly moved to position and formed a protective ring around the Gate.

The tanks were Mitsubishi Type-74s and while they are outdated compared to other modern battle tanks, they are nevertheless quite effective. Thanks to researching into the remains of the dragon killed in Ginza, both their main guns and HEAT rounds were deemed capable of piercing through the scales of any other dragon that they encounter.

As for the vehicles, they consist of Komatsu LAVs, Type 96 APCS, Mitsubishi Type 73s and Toyota HMVs; the first two were armed with heavy machine guns while the latter was unarmed.

Since the end of World War II, Japan has never been involved in a single conflict. So as of today, the expedition would essentially be the JSDF's first official military operation.

As of now, the first detachment of the Special Task Force consists of several hundred soldiers along with a few dozen vehicles and tanks. Once the area is properly secured, additional support and supplies would be provided.

While lacking real-life combat experience, the JSDF are nevertheless well-trained and are likely about handle whatever dangers that the Special Region could throw at them.

Most of the soldiers of the Special Task Force were armed with Howa Type 64 assault rifles, but the rest were equipped with Sumitomo Minimi light machine guns to provide suppressing fire.

Not only that, several mortar teams and snipers also took part in the expedition to provide long-range support.

Just when everything around the Gate appeared to be clear, one of the tanks covering the west side quickly reported to everyone on the radio.

"This is Alpha 3! There is some sort of lighting on the top of that hill!"

Very soon, the soldiers disembarked their transports and IFVs with their weapons ready; all taking up defensive positions across the western perimeter.

Hazama wasn't sure if whatever is on the hill is hostile, but he nevertheless ordered all vehicles and tanks to hold their original positions and maintain the defensive ring. If something hostile try to attack from another side, they would be able to at least hold them off until some soldiers can be repositioned to provide additional support.

It may not be a sound strategy, but one has to make compromises when it comes to holding a position in the middle of a plain, where the enemy could flank them at an undefended gap in the perimeter.

"See anything?"

"I think so... What the hell?"

Taking position behind a formation of rocks along with other soldiers were 1st Lieutenant Yōji Itami and Sergeant First Class Ryuu Takara.

The two were distinguished for their actions during the dragon's arrival in Ginza two months ago. After all, they were the very soldiers that help distract the dragon long enough for the gunships to arrive while saving their wounded from certain death.

As recognition for their bravery, skills and quick thinking, the Minister of Defense personally promoted the two on live television. Prior to the attack, Itami was a 2nd Lieutenant while Ryuu was a Sergeant.

Itami was viewed in the JSDF as a lazy otaku whose work performance was deemed barely acceptable by his superiors. Even so, his bravery in saving his injured comrades and coordinating the men is nevertheless admirable.

Ryuu however was the opposite for he was known for his exceptional marksmanship despite being the age of twenty-two. While he is somewhat laidback, he understands his responsibilities and is quite active while on-duty.

It was no surprise that his superiors learn about his accomplishment in blinding the dragon during the incursion and were quick to recommend him to be trained as a sniper.

Regardless, by the time the expedition to the Special Region begun, he has already completed his training and was one of the top marksmen in his class upon graduating just a few weeks prior today.

Armed with a M24 Sniper Weapon System, he was scanning the hill with his telescopic sight, but without any night vision, Ryuu had to rely on the specks of light to provide some form of illumination.

While he was able to partial glimpse what was on the hill, he was very surprise to see what was in his scope.

"What is wrong?" Itami asked.

"This can't be right..." Ryuu said as he maintained visual contact on the hill. "I think I see fellow humans, but they appear to be wearing medieval armor..."

The Lieutenant was dumbfounded at the notion, but he looked through his binoculars and saw it was indeed the truth. "You got be kidding me..."

Those with their own soon followed suit and were now reporting in the same thing. However, they also report that a number of people begun to descend down the hill and it was slowly growing in size.

Wanting to see with his own, Hazama disembarked his LAV and looked through his binoculars, where he saw there were indeed medieval soldiers and knights moving to the base of the hill.

From their movements, it appeared they were getting into battle formation.

'Seems we have alerted them...'

Hearing through the radio chatter, Hazama surmised that the noise generated from the vehicles and tanks caught the attention of those on the hill. Based on their movements, they viewed his task force as a threat.

Hazama did warn his men prior to the expedition about unknown dangers within Special Region and they must be ready for combat at a moment's notice. As much he wanted to avoid hostilities with the inhabitants, this battle is clearly unavoidable.

Across the western perimeter of the Gate, the mortar teams were quickly preparing their L16 81mms with illumination rounds, the tanks were loading their rounds and every soldier was checking that their rifles and LMGs were fully loaded.

As for the snipers and those with binoculars, they continue to monitor the hill and observe the mass of plate-armored knights armed with lances taking position at the bottom of the hill.

They couldn't tell, but behind the knights were a much larger mass of foot soldiers with their swords, spears and bows ready.

Almost a kilometer away from each other, both sides have their respective advantages as they prepared themselves for battle. The enemy army numbered in the thousands, yet the JSDF have both range and firepower despite being outnumbered.

"This isn't going to end well for them..."

Itami muttered as he looked through his binoculars at the enemy formation. While it would be a fearsome sight back then, but it is no longer the case when up against modern weaponry.

"True that. It is going to be a bloodbath..."

Ryuu replied as continue observe through his scope. He already read through enough military history books that mass cavalry charges against automatic fire is suicide.

There was a reason why knights became obsolete hundreds of years ago on Earth and these fools are about to learn it the most painful way possible.

With that said, the enemy army didn't hesitate in making the first move as their knights begun to charge forward; their shouts and the galloping of their horses was heard across the plains.

However, it was soon replaced by much louder and more terrifying sound as the mortar teams provided much needed visibility with their illumination rounds, which startled everyone throughout the enemy formation.

"Special Task Force! Engage!"

Upon hearing Hazama's order, everyone at the western perimeter begun to fire their weapons at the charging knights.

"Load HE, 700 Meters! Fire!"

One of the tanks fired its round at the knights in the enemy's formation, resulting in the scattering of dirt, broken bodies and severed limbs. The rest of the tanks followed suit and with their explosive rounds alone, they killed hundreds of medieval warriors in a matter of seconds and rising.

"Maintain your fire!"

Those not decimated by the tanks were instead cut down by the bullets and tracers fired from the JSDF firearms. The soldiers maintain fire with their rifles and LMGs while the LAVs and APCs were unleashing high-caliber rounds with their HMGs. The enemy could only look in horror at their comrades being riddled with holes with blood gushing out.

"Half load! Fire!"

For the mortar teams, they switched their high-explosive rounds and were barraging those positioned in both the center and rear of the enemy formation. Foot soldiers and archers who thought themselves safe from the front lines soon found themselves being blown into pieces as the survivors were showered in dirt and gore.

For Ryuu and his fellow snipers, it was difficult to use their skills to the fullest due to the lack of elevated positions. They are only able to aim at the knights in the front line, who are very likely to be killed before they could pull trigger. Nevertheless, they did their job as they took aim at either a knight or his horse and fired their shots.

Against this deadly combination, the hostile army never stood a chance. Not only that their plate armor and wooden shields were completely worthless, the JSDF were beyond the range of what few archers they have left.

Within a few minutes, the bodies of thousands of medieval soldiers and knights now littered the base of the hill with their broken weapons and shields.

Craters were sown across the entire area with the grass being adorned with served limbs, gore and blood.

The cries and screams of the injured and dying could be heard; either begging for help or for someone to end their pain.

Demoralized and broken from the hellish experience from modern weaponry, the remnants of the enemy army quickly threw down their weapons, took off their armor and ran for their lives.

If anything, they were fighting a hopeless battle against an otherwise demonic army.

"The enemy's formation is broken! Ceasefire!"

Now that the enemy was fleeing the plains, Hazama ordered his men stop firing for there was no point in continuing one this one-sided battle.

"My god..."

Through his scope, Ryuu looked upon the aftermath of the carnage that the JSDF just brought forth. Many of the soldiers felt the same way for they never seen such carnage before in their lives.

Even though it was in an act of self-defence, some were worried of public opinion back home when the government learns about this battle.

"General, should we search for any survivors?"

Akira asked Hazama, who was about reply when he was interrupted by an urgent report from on the tanks at the western perimeter of the Gate.

"This is Alpha 11! Spotted movement to the west!"

"Tsk... Please let them be friendlies."

"We can only hope..." Hazama shares his Lieutenant's concerns, but he ultimately prepared himself for the worse. "All infantry, reinforce the eastern perimeter!"

Every soldier hastily relocated to east of the Gate and took up new defensive positions. While much ammunition was used in the last battle, they still have a handful of magazines left.

Ryuu looked through his scope once again prone on the ground, but couldn't make out anything without any form of illumination in the distance. All he could tell from the silhouettes that it was indeed another medieval army, who was about like half a kilometer away from their position.

When the mortar teams once more fired another set of illumination rounds over the potentially hostile army, Ryuu was bewildered as he finally caught of the one who was apparently leading them.

It was a beautiful young girl whose hair almost appeared to be of pure silver. Unlike the rest of the knights, she wore a revealing blue outfit while wielded an ornate-looking longsword.

She was looking up in surprise at the illumination rounds along with the rest of the knights. However, she regains her composure and was now preparing the army to charge. Raising her longsword into the air, the girl finally gave the order to attack.

Wasting no time, Hazama ordered his men to again open fire and repeat the same carnage that inflicted just moments ago.

The other medieval army barely had any time to start their charge as they were struck by the JSDF's relentless defense. In a few moments, hundreds of knights and their horses were now dropping like flies or thrown into the air like discarded trash.

Even though they number in the thousands like the previous and outnumber the JDSF, they were hopelessly outgunned by superior technology and firepower.

Ryuu maintained visual on the silver-haired girl despite the chaos of the battle; seeing the shock and horror on her face while the army was being decimated. Even though she was a clearly a beauty to behold, she was unfortunately an enemy.

"Sorry about this..."

Aiming for center mass, Ryuu then fired his M24 at the silver-haired girl.

In the last second however, she shifted to the left due to the force from a mortar and the shot struck in the upper left arm instead. Even so, the force was strong enough to knock off her horse and fell onto the ground hard.

Not giving her an opportunity to escape, Ryuu shifted his sight onto her horse and shot it straight to its head. By a stroke of luck, the horse ended up collapsing dead on top of the girl and pinned her down.

Through his scope, he notices a group of knights noticing the downed girl and begun to rush to her aid. Unfortunately for them, they were quickly decimated by an incoming tank round.

The rest of the knights would share their fate for in the next few minutes, their losses were now numbering in the thousands and were steadly growing.

The survivors tried to organize a retreat, but it quickly turned into a rout as they broke rank and fled; leaving their maimed and wounded behind.

"Ceasefire!" Hazama's order as his men halt their fire and let the scattered survivors go back where they came from.

It just been less than an hour since the Special Task Force first arrived in the Special Region and they already decimated two medieval armies in a matter of minutes. They inflicted massive casualties and while suffering none of their own.

It was the JSDF's first taste of an overwhelming victory.

 **OOOOOOOOOO**

After seeing that their position was indeed secured, Hazama was able to call in additional reinforcements from Japan. As the newly arrived combat engineers were in the process in setting up basic fortifications like towers and trenches around the Gate, the medics were attached to search parties that were currently looking for any survivors from the last two battles.

Since the two armies attacked them without proclamation, the JSDF would treat the survivors as prisoners of war. Nevertheless, the prisoners would receive proper medical attention and be treated with respect and dignity till they are released.

Among these search parties were Itami, Ryuu and two other soldiers; Sergeant Takeo Kurata and Sergeant First Class Mari Kurokawa.

Ryuu knew that thee former to be as much as an otaku as Itami, but he knows little about the latter besides the fact that she is a combat medic.

When Itami asked where they should start first, Ryuu decided to tell him and others about the silver-haired girl and lead them to her location.

Since he shot her in the arm, there was the likely chance that she is still alive despite the carnage a few minutes ago. However, there was the chance she was dead due to the concussion force of an explosion or a stray shrapnel.

Luckily, they found the silver-haired girl to be still alive and relatively intact disregarding her previous inflicted by Ryuu. However, she was unconscious and her legs remained pinned by the weight of her dead horse.

After Itami, Ryuu and Takeo lift the large corpse off the girl's legs long enough for Mari to pull her out, the medic then checked on her health.

"She has a concussion, but doesn't appear to have a skull facture... Her legs are not broken... There is also a bullet wound through the upper part of her left arm..."

Mari said as she continues her examination on the silver-haired girl. As for the rest of the group were scanning the area for any other survivors.

"I never seen a girl like that before... It is like she came straight out from an anime." Takeo commented after he first laid eyes on the unknown girl. "Ryuu, are you really sure she is a leader? I don't think she is even eighteen."

"I'm not very sure to be honest, but she was in front of the army and they apparently obeyed her when she ordered the charge." Ryuu replied. "I even saw a group of knights rushing in to help her, but ended up getting blown up by a tank round."

While Ryuu and Takao were talking about the girl, Itami continued to survey the corpse-littered plains before he notices something move at the left corner of his eye just five meters away.

"Movement!"

He called out to everyone as he pointed to what appears to be young female knight struggling to get up. Appearance-wise, she was eye-catching and appears to be almost into her twenties.

Her long blonde hair was styled into a left-side ponytail, but was slightly messed up and covered with dirt. While her armor had some dents and blood stains, there weren't any signs of injuries on her body.

If anything, the group can't help to think that this knight was lucky beyond imagining for she manages to live through the entirety of the battle.

Upon seeing them and the silver-haired girl that Mari was tending however, she quickly grabbed a sword that laying by her side and forced herself back up on her feet despite the pain throughout her body.

She begun to yell at them in an unknown language as she glared angrily at the JSDF soldiers.

In response, Itami and Takeo raised their rifles while Ryuu drew his Minebea P-9 instead. While he had his M24 strapped over his right shoulder, it wasn't meant for close range combat. Mari in the other hand didn't have a weapon with her, so she had to go behind the three men for protection.

"Drop your weapon and put your arms in the air! Surrender and you'll not be harmed!"

Ryuu called out at the female knight to surrender, but she instead shouted back; like she was cursing him and the rest of the group.

"She doesn't understand Japanese." Mari noted.

"And we don't have clue what she's saying either." Itami followed up.

"Then what should we... Look out!" Takeo cried out as the female knight made a battle cry as she charged at them; her sword readied for an overhead strike.

Before she could take a slash at them, Ryuu ran quickly delivered a tackle; the force from the impact caused her to drop her sword.

Down on the ground, she tried to break free from the sniper's grip and became more frantic when Itami ran up and put her in a neck lock.

Takeo then followed up with swift yet hard blow to the head with the stock of his rifle, knocking her out cold. Mari though went up to check on the knight to see if she ended up having any significant head injuries from the blow.

After getting confirmation from her that the knight would be alright, Ryuu used a handcuff that he carried with him to restrained her hands behind the back. Mari in turn was applying first aid to the silver-haired girl.

Tending to the bullet wound on her left upper arm, she stemmed the bleeding by tying a tourniquet on her upper left arm, clean the wound with some disinfectant and then bandaging it

It was the best that Mari could do to keep her stabilized long enough to be transferred to Japan for proper medical treatment.

After loading both the unconscious girl and knight onto a nearby transport, the group then continued on their search for survivors across the blood-soaked battlefield that they and the rest of JSDF brought forth.

For the next few hours, the JSDF searched through both the eastern and western side of the plains. While they found approximately a thousand medieval soldiers and knights to be still alive, the majority of them were critically wounded and can't be saved.

Only a few hundred were successfully recovered and be given first aid before being transferred to Japan and receive full treatment at a hospital.

There were a handful who just had superficial injuries, but became hostile upon seeing the JSDF search teams. Luckily, they were all taken down non-lethally and are at the moment being transferred also to Japan, where they would be sent to holding cells for questioning.

Wile there is still the issue regarding the language barrier between the JSDF and the Special Region's locals, but it is hoped that it would be resolved soon by questioning the survivors. With what they experienced today, it is obvious that it would take a while before they would ever cooperate with the Japanese.

It would be the first of many hurdles that the JSDF will have to resolve as they began to establish their first foothold in the Special Region.

* * *

 **Author Note**

 **Merry Christmas everyone!**

 **I been spending the last few weeks looking through my other stories and ended up making a few decisions. For one, I'm going to discontinue some of my stories, which are Point of Divergence, The Realms Beyond and Dimensional Omega. However, I'm not going to remove them, so anyone can still read them if they wish. It is just these stories will not be updated anytime soon.  
**

 **Regarding Dimensional Omega, I still viewed it a good idea yet I feel my first attempt at it is flawed. Feeling some inspiration, I chose to write a revision of the story and made it a true GATE/Vanadis crossover. I also had ideas of using the concept of Dimensional Omega in a proper GATE/** ** **C &C crossover, but I have yet to decide to go through with it.  
****

 ** **Either way, I'll leave it to you all to decide if my revision is an improvement compared to the original. I hope you enjoy it.  
****


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